1 files changed, 32 insertions, 0 deletions
diff --git a/racket/aoc2021/day-22/day-22.rkt b/racket/aoc2021/day-22/day-22.rkt
new file mode 100644
index 0000000..1dc4211
--- /dev/null
+++ b/racket/aoc2021/day-22/day-22.rkt
@@ -0,0 +1,32 @@
+#lang racket
+(require "../../jj-aoc.rkt"
+         threading)
+
+(struct step (instruction xs ys zs) #:transparent)
+
+;; part 1
+(define (clamped-range nmin nmax)
+  (in-inclusive-range (max (string->number nmin) -50)
+                      (min (string->number nmax) 50)))
+
+(define steps
+  (for/list ([l (in-list (~> (open-day 22 2021) (port->lines)))])
+    (~>> l
+         (regexp-match #px"(.+) x=(-?\\d+)..(-?\\d+),y=(-?\\d+)..(-?\\d+),z=(-?\\d+)..(-?\\d+)")
+         rest
+         (match _ [(list direction xmin xmax ymin ymax zmin zmax)
+                   (step (string->symbol direction)
+                         (clamped-range xmin xmax)
+                         (clamped-range ymin ymax)
+                         (clamped-range zmin zmax))]))))
+
+(~> (for*/fold ([cubes (hash)])
+               ([s (in-list steps)]
+                [to (in-value (step-instruction s))]
+                [x (step-xs s)]
+                [y (step-ys s)]
+                [z (step-zs s)])
+      (hash-set cubes (list x y z) to))
+    hash-values
+    (count (curry equal? 'on) _))
+